1. Field of the Invention
The invention relates to high pressure pipelines. More particularly, the present invention relates to pipe blinds.
2. Description of the Related Art
Pipe blinds are known in the art. In the refining and petrochemical industry, blinds are used to completely stop the flow through a pipe in order to remove a piece of equipment from service. This piece of equipment could be a valve, heat exchanger, pipeline, distillation tower reactor, or the like. The blind insures that no combustible or toxic material will enter equipment or flow onto personnel working in or on equipment. Blinds are installed between the equipment being repaired and the first block valve or set of flanges upstream of the equipment.
One side of a blind is always considered to be live. This means that pressure is present, or the potential for pressure exists. Before a blind can be removed after the work is completed, the live side must be de-pressured. If no bleed valves exist between the blind and first block valve, the flange bolts at the blind must be loosened carefully to allow for the pressure to escape to the atmosphere. When a portion of a line has to be replaced, temporary bleed valves have to be installed at high and low points to allow for filling and bleeding off air when lines have to be hydrostatically tested before being put into service. High point bleeders are sometime left in place and the valve plugged to prevent valves from leaking to the atmosphere. When valves are removed, a plug is installed and backwelded to prevent leakage. Both of these methods are used today and both are potential sources of hydrocarbon emissions to the atmosphere.
U.S. Pat. No. 4,452,278 discloses a spectacle line blind with vent which includes a pivotable or rotatable spectacle plate having at one end a conventional full opening providing little obstruction to flow of liquid or gas. On the other end of the spectacle valve plate a blank disc seals one of the inlet and outlet ducts. The opposite side of this blank disc includes spacers having axial and radial openings there between which permit gases to vent to the atmosphere from the other duct.
U.S. Pat. No. 3,891,146 discloses a pipeline apparatus having an economical fitting which makes it possible to carry out certain functions without shutting down the pipeline. Certain installations may require an operating mechanism for operating it. The operating mechanism may be a rather expensive apparatus. In one embodiment of the invention the operating mechanism is attached to the operated structure for only short periods of time and then disconnected therefrom, leaving the operated structure in its functioning condition in relation to the pipeline. Thus a single operating mechanism may be used for operating each of a number of different structures or fittings from time to time as required. The fitting has a seat for temporarily seating the operating mechanism onto the fitting while the fitting is under pressure for performing various equipment changes or other operations of the fitting.
U.S. Pat. No. 3,695,299 discloses a pipe-line blind valve, for blanking off pipe-lines, in which a plate having a hole of the same diameter as the pipe-line is movable from one position, in which the hole is aligned with the bore of the pipe-line, to a second position in which the pipe-line is blocked off, there being a seal to seal between the pipe-line and the plate.
U.S. Pat. No. 2,614,423 discloses a fluid flow orifice structure for arrangement in a conduit to measure the flow of fluid therein, a plate for insertion in the conduit across the flow area through which the fluid in the conduit passes, the plate having a central opening through which the fluid passes and a plurality of passages radially arranged about the center of the plate at spaced intervals, the plate having ports for measuring the impact pressure of the fluid flowing through the conduit, the impact pressure ports positioned in radial series one above the other in the flow area between the center of the plate and the periphery thereof, the impact pressure ports assuming circumferentially spaced circular series of ports around the center of the plate, each radial series of ports communicating with a radially disposed passage, the plate at the periphery thereof having an annular impact pressure channel, each radially disposed passage communicating with the annular impact pressure channel, the plate having a plurality of second passages radially arranged about the center of the plate at spaced intervals and equal in number to the number of first mentioned radially arranged passages, the plate having second ports for measuring the static pressure of the fluid flowing through the conduit and equal in number to the number of the impact pressure ports, the static pressure ports positioned in radial series one above the other in the flow area between the center of the plate and the periphery thereof, the static pressure ports positioned in radial series one above the other in the flow area between the center of the plate and the periphery thereof, the static pressure ports assuming spaced circular series of ports around the center of the plate, each circular series of static pressure ports having a diameter equal to the diameter of a corresponding circular series of impact pressure ports, each radial series of second mentioned ports communicating with a radially disposed second mentioned passage, the plate having an annular static pressure channel, each radially disposed second mentioned passage communicating with the annular static pressure channel, the impact pressure ports and the static pressure ports being open on opposite sides of the plate, respectively, a device for connecting the annular impact pressure channel to one side of a metering mechanism and a second device for connecting the static pressure channel to the metering mechanism.
U.S. Pat. No. 2,462,731 discloses a diversion blind fitting for a pipe line, having flanged joints, the fitting including a body, the body having bolt holes extending laterally therethrough, the bolt holes matching holes in the flanged joints of the pipe line, whereby the body is mounted in the pipe line, a pipe extension to which a pipe is attached, the pipe extension and body having a duct extending therethrough, the duct extending through one side of the body only, and a solid wall on the other side of the body whereby the entire flow through the pipe line is directed through the duct.
U.S. Pat. No. 2,278,849 discloses a line blind for connection in a pipe line including two tubular sections arranged in end to end relation to define a fluid passage and related for relative longitudinal movement, a device for connecting the sections with spaced members of the pipe line, a plate having an imperforate disc-like portion adapted to be inserted between the opposing ends of the sections to extend across the passage, and a device for moving the sections toward and away from one another to clamp the plate between the ends and to free the plate for removal, the device including flanges on the ends of the sections, a rotatable sleeve in surrounding relation to the flanges, the sleeve having a transverse slot in its wall for passing the portion of the plate to and from the position between the ends of the sections, the edge of the plate portion being engageable with the internal surface of the unslotted part of the sleeve to center the plate portion between the ends, an inturned lip on the sleeve having one side bearing against the outer end of the flange of one section, a collar on the section engaging the other side of the lip, and cooperating threads on the sleeve and the flange of the other section.
U.S. Pat. No. 1,164,033 discloses a valve connection mechanism including a pipe cap device, having separable cut off slide receiving members and adapted to receive auxiliary piping and a cut off slide adapted to force the members apart and enter between them to close the pipe outlet, whether the auxiliary piping is engaging the connection mechanism or not.
U.S. Pat. No. 1,150,141 discloses a plate valve which is the combination of two pipes, an angular ring rigidly secured to an end of each pipe, an undercut peripheral flange on each of the rings, a plate located between the ends of adjacent pipes, and a turnbuckle for drawing the pipes into close engagement with the plate, the turn buckle being provided with undercut recesses adapted to engage the flanges, substantially as described.
U.S. Pat. No. 913,866 discloses a valve for the purposes described including a casing and a closure adapted to be detachable held to seat therein by a device carried by the closure and completely housed by the casing when the closure is seated, the closure and holding device being bodily removable from the casing, and the casing being adapted to form a substantially unobstructed coupling in a pipe line when the members are withdrawn.
U.S. Pat. No. Re. 25,052 discloses an additive control device which is a flow control device for disposal in a liquid flow line including a housing consisting of a pair of substantially identical rectangular plates having a constant thickness over a major portion of its area, the plates having smooth inner surface areas facing each other, a circular disk disposed between the plates, the disk having parallel flat surfaces for engagement with the smooth surface of the plates, the width of the plates being less than the diameter of the disk whereby the periphery of the disk will project beyond the side edges of the housing for enabling rotation of the disk, each plate having a liquid flow opening therein adjacent one end thereof with the openings being aligned with each other, tubular adapters connected with each of the plates in alignment with the opening for providing a liquid flow path, the and being adapted to connect to a liquid flow line, the disk having a central opening, each of the plates having and opening therein in alignment with the central opening in the disk, a device extending through the openings in the plate and the central opening in the disk for rotatably retaining the disk and urging the plates towards the disk, the end edge of each plate adjacent the tubular adapter having a laterally extending apertured ear disposed radially outwardly of the periphery of the disk, a clamp device extending through the ears for urging the plates towards each other adjacent the end edge having the tubular adapters thereon, each of the plates having an annular recess in the smooth inner surface area thereof with the recess being disposed in spaced concentric relation to the liquid flow opening, an O-ring seal in each recess, the seal being constructed of resilient material and projecting beyond the surface of the plate for frictional sealing engagement with the disk, the disk having a plurality of circumferentially spaced orifices extending therethrough, the orifices being disposed for alignment with the liquid flow openings and being of different sizes, the spacing between the orifices being greater than the diameter of the O-ring seal whereby only a single orifice can be encircled by the seal, numerical indicia on the disk radially outwardly of the orifices for indicating the size of the orifices, a plurality of knobs on the periphery of the disk for aiding in the rotation thereof, the end edge of each plate remote from the tubular adapters having a notch therein revealing the periphery of the disk and the numerical indicia thereon, a pointer in the notch for alignment with the indicia for indicating alignment of a diametrically opposed orifice with the liquid flow path and the size of that orifice, each of the orifices being countersunk on the downstream side thereof to facilitate escapement of liquid from the orifice, the smooth inner surface area of each plate disposed radially outwardly of the periphery of the disk extending longitudinally inwardly and terminating in flat surfaces disposed adjacent each other for maintaining the plates and disk in generally parallel relation whereby the entire periphery of the O-ring will engage the disk.